Method and System for Optimizing Routing of Data Packets

ABSTRACT

A method and system for determining a route for a packet traveling over at least one system from a source to a destination is disclosed. A first geographic area corresponds to the source and a second geographic area corresponds to the destination. The destination further has an address which does not indicate the second geographic area. In this aspect, the method and system include associating an address for the destination with the second geographic area to allow selection of the route for the data packet based on the second geographic area and selecting the route based on a second geographic area. In a second aspect, the method and system include providing a direct link having a controllable amount of traffic and selecting the direct link as at least a portion of the route when a data packet to the destination is to be routed. The method and system also facilitate selection of a route for a data packet. In this aspect, the method and system include obtaining information relating to an autonomous system. The autonomous system has a geographic area. The information includes the geographic area. In this aspect, the method and system also include associating the autonomous system with the geographic area to allow selection of the route based on the geographic area.

RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 11/013,361 filed Dec. 17, 2004 (“Method and System forOptimizing Routing of Data Packets”), issued on Nov. 24, 2009 as U.S.Pat. No. 7,623,528, which was a continuation of U.S. patent applicationSer. No. 09/580,990 filed May 26, 2000 (“Method and System forOptimizing Routing of Data Packets”), issued Mar. 22, 2005 as U.S. Pat.No. 6,870,851, which was a continuation of application Ser. No.09/151,935 filed Sep. 11, 1998 (“Method and System for OptimizingRouting of Data Packets”), now U.S. Pat. No. 6,130,890, issued Oct. 10,2000, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to routing of data packets, and moreparticularly to a method and system for improving routing decisions,particularly for Internet data packets traveling to a destinationassociated with another country.

BACKGROUND OF THE INVENTION

Information can be transferred between users at different locationsusing different types of communication networks. The information beingtransferred typically includes addressing information that indicates thelocation to which the information is to be relayed. This addressinginformation allows the network to route the information to the intendedrecipient.

The communications networks which transfer information include a numberof interconnected nodes. A node is a location in the network at whichincoming information, such as a stream of data packets, can flow outover one of a plurality of paths. A node contains sufficientintelligence to decide how to choose one of the paths based on theaddressing information and the technology used in the network. Thus, thenode decides how to route the information. The information may be routedto a next node, traversing the communication network, to arrive at thedestination.

One such communication network is a conventional public switchedtelephone network (“PSTN”). In the conventional PSTN the node is aconventional telephone switch. The routing decision made by the node isfor the setup of a telephone call. The addressing information on whichthe decision is based includes a callee's telephone number. Typically,the callee's telephone number is ten digits. These ten digits include athree digit area code and, in the United States, a three digit exchange.In a conventional PSTN, there is a strong correlation between phonenumbers and geographic location. For example, in the ten-digit telephonenumber, the area code specifies a geographic region. The exchangespecifies switches for a portion of the geographic region. Thedestination, the callee's telephone, is in this portion of thegeographic region. In general, when more digits of a phone number arespecified, the geographic location of the telephone switch which ringsthe callee's telephone is better determined. Thus, the nodes in theconventional PSTN use the callee's telephone number to route the calldirectly to a geographic region close to the known physical destinationof the phone call. Conventional telecommunications Switches ensure thata call does not take an excessively long and inefficient path to thecallee.

A communication network which utilizes computers is the Internet. Datapackets can be transferred between two locations, a source and adestination, via the Internet. The Internet can be viewed as acollection of systems which are compatible with the Internet Protocol(“IP”). The Internet allows for a wider variety of services than otherconventional communications networks such as a PSTN. The Internet shouldalso be more fault-tolerant, and allow for a broad range of speeds andtransmission media than a PSTN.

Each data packet transferred via the Internet includes addressinginformation. The addressing information in the data packet includes adestination address for the data packet's destination. The destinationaddress includes an IP address of the destination. An IP addresscontains four integers, with the integers being separated by periods.Each integer is from zero to two hundred and fifty-five. For example, anIP address and, therefore, a destination address is 202.123.123.6.

IP addresses are typically assigned to autonomous systems (“ASs”) withinthe Internet. An autonomous system is a collection of IP addresses andIP-capable devices and communications links under a singleadministrative domain. An autonomous system assigned the IP addressesmay also be an Internet Service Provider (“ISP”). A particular AS may beassigned a range of IP addresses. For example, a single AS may have theIP addresses 202.123.4.0 through 202.123.7.255. In order to ensure thatinformation is routed to the correct destination, each AS must be ableto determine how to reach the autonomous system that is assigned thedestination address. Therefore, the ASs of the Internet tell each otherhow to find every IP address range in the Internet. Each AS announcesits range to the entire Internet, declaring that “if you have trafficbound for one of these IP addresses, send it to me.” Other ASs use thisinformation to ensure that the data packet reaches the AS assigned thedestination address and, therefore, the destination.

There are multiple routes which a data packet can use to traverse theInternet. A route includes the ASs that a data packet travels through inorder to reach the destination. Typically, a router acts as a nodethrough which the data packet can access multiple routes to thedestination. Using the IP packet's destination address, the routerswithin the Internet determine how to route the data packet to the ASassigned the destination address and, therefore, the destination. A datapacket may pass through a series of routers before reaching thedestination. Certain conventional routers select the route such that thefewest number of ASs are crossed before reaching the destination.

Although the Internet is capable of transmitting data packets from asource to a destination, the routing may be slow or may result in datapackets being lost. There is no geographic correlation between thedestination address and the physical location(s) associated with the ASassigned the destination address. IP addresses may come in clustersbecause a range of IP addresses maybe assigned to the same AS. Forexample, an AS in Japan might be assigned the IP address range of202.123.4.0 through 202.123.7.255. However, no convention specifies thatall IP addresses of a particular range will be in an AS associated witha specific country or other geographic region. Therefore, similardestination addresses could correspond to destinations which are widelyseparated geographically. Nothing about a destination address impliesthe geographic location of the destination or the geographic location ofthe AS that is assigned the IP address of the destination.

In part because destination addresses are not linked to geographicareas, routers can make non-optimal routing decisions. Non-optimalrouting may slow down the end-to-end Internet traffic stream or routethe traffic over congested links. As discussed above, routers use thedestination address in order to determine routing of a data packet.However, the destination address contains no information relating to thegeographic area of the destination, the geographic area of the AS forthe destination, or the geographic area of the routers between thesource and the destination. As a result, a router may select a routethat forces a data packet to travel a very large distancegeographically. For example, to reach a destination having an IP addressassigned to a first AS in Great Britain, a data packet originating in asecond AS in the United States may travel to a third AS in then to thefirst AS in Great Britain because this route has the fewest ASs. Becausethe data packet travels such a large distance, transmission of thepacket may be slowed. In addition, the data packet may cross a number ofinternational links, which typically have a very high link utilization.As a result, the data packet may be lost or the transmission of the datapacket may be slowed.

Accordingly, what is needed is a system and method for more efficientlyrouting packets. The present invention addresses such a need.

SUMMARY OF THE INVENTION

The present invention provides a method and system for determining aroute for a packet traveling over at least one system from a source to adestination. A first geographic area corresponds to the source and asecond geographic area corresponds to the destination. The destinationfurther has an address which sloes not correspond to the secondgeographic area. In this aspect, the method and system compriseassociating an address for the destination with the second geographicarea to allow selection of the route for the data packet based on thesecond geographic area.

In a second aspect, the method and system comprise providing a directlink having a controllable amount of traffic and selecting the directlink as at least a portion of the route when a data packet to thedestination is to be routed.

In another aspect, the method and system function in an Internetenvironment. In this aspect, the source has a first Internet Protocol(“IP”) address assigned to a first autonomous system and the destinationhas a second IP address assigned to a second autonomous system. Thefirst autonomous system has a first geographic area, and the secondautonomous system has a second geographic area. In this aspect, themethod and system comprise obtaining the second geographic area for thesecond autonomous system, mapping the second geographic area to thesecond autonomous system such that the route can be selected based onthe second geographic area, and selecting a direct link to a thirdautonomous system having the second geographic area for at least aportion of the route. The method and system also facilitate selection ofa route for a data packet. In this aspect, the method and systemcomprise obtaining information relating to an autonomous system. Theautonomous system has a geographic area. The information includes thegeographic area. The method and system further comprise associating theautonomous system with the geographic area to allow selection of theroute based on the geographic area.

According to the system and method disclosed herein, the presentinvention may route packets such that the packets are delivered to theirdestination more quickly and with leis probability of being droppedduring transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a portion of the Internet in which thepresent invention can be used.

FIG. 2 is a flow chart of a conventional method for selecting a routefor transferring a data packet from the source to the destination.

FIG. 3 is a flow chart depicting one embodiment of a method forselecting routes based on geographic area in accordance with the presentinvention.

FIG. 4 is a more detailed flow chart of one embodiment of a method inaccordance with the present invention for selecting a route for a datapacket.

FIG. 5A is a flow chart depicting one embodiment of a method forselecting routes in accordance with the present invention.

FIG. 5B is a more detailed flow chart of one embodiment of a method forselecting routes in accordance with the present invention.

FIG. 6 is a flow chart depicting a preferred embodiment of a method inaccordance with the present invention for selecting a route based ongeographic area.

FIG. 7 depicts a more detailed flow chart of the preferred embodiment ofa method in accordance with the present invention for selecting a routebased on geographic area.

FIG. 8 depicts one embodiment of a method in accordance with the presentinvention for selecting a route based on geographic area when theautonomous system is not directly connected to the country of theautonomous system associated with the destination.

FIG. 9 is flow chart of one embodiment of a method in accordance withthe present invention for associating a geographic area with an address.

FIG. 10A is flow chart of one embodiment of a general method inaccordance with the present invention for associating a geographic areawith an address using an external database.

FIG. 10B is flow chart of a preferred embodiment of the method inaccordance with the present invention for associating a geographic areawith an address using a first external database.

FIG. 10C is flow chart of a preferred embodiment of the method inaccordance with the present invention for associating a geographic areawith an address using a second external database.

FIG. 10D is flow chart of a preferred embodiment of the method inaccordance with the present invention for associating a geographic areawith an address using a third external database.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an improvement in routing of packetsover the Internet, particularly those packets to destinationscorresponding to another country. The following description is presentedto enable one of ordinary skill in the art to make and use the inventionand is provided in the context of a patent application and itsrequirements. Although the present invention will be described in thecontext of a particular embodiment, various modifications to thepreferred embodiment will be readily apparent to those skilled in theart and the generic principles herein may be applied to otherembodiments. Thus, the present invention is not intended to be limitedto the embodiment shown, but is to be accorded the widest scopeconsistent with the principles and features described herein.

FIG. 1 is a simplified block diagram of a portion of the Internet 10that can be used for transferring data packets (not shown) betweendifferent locations such as the source 11 and the destination 34. TheInternet 10 includes a plurality of autonomous systems (“ASs”) 12, 20,22, 26, 28, and 32. The ASs 12, 20, 22, 26, 28, and 32 areinterconnected to form the portion of the Internet 10 shown. An AS 12,20, 22, 26, 28, or 32 may be connected with specific locations. Forexample, the AS 12 and the AS 32 are connected with the source 11 andthe destination 34, respectively. The AS 12 is connected to the AS 20,the AS 22, and the AS 28 through links 15, 16, and 17, respectively. TheAS 12 is said to be directly connected to the AS 20 because there is aroute between AS 12 and the AS 20 which does not pass through another ofthe AS 22, 26, 28, and 32. A route is a logical path that a packet maytake from a source to a destination. The AS 22 is connected to the AS 26and the AS 20 via Network Access Point (“NAP”) 24, link 23, and links 25and 35, respectively. The AS 28 is connected to the AS 32 via NAPs 30and links 29 and 31. NAPs 24 and 30 are more fully described below. TheAS 26 is directly connected to the AS 20 and the AS-6 32 via links 21and 27, respectively.

An AS 12, 20, 22, 26, 28, or 32 often includes one or more enterpriseunits such as a university, a corporation, or some other organization.However, each AS 12, 20, 22, 26, 28, or 32 may also contain multiplegeographically dispersed, unrelated organizations. An AS 12, 20, 22, 26,28, or 32 may also be assigned one or more ranges of Internet Protocol(“IP”) addresses. For example, the AS 12 is assigned the IP address ofthe source 11. The AS 32 is assigned the IP address of the destination34. An AS 12, 20, 22, 26, 28, or 32 may also be considered to include atleast one router under a single technical administration. For example,the AS 12 and the AS 32 are depicted as having routers 14 and 33,respectively. Although not shown, other routers may exist in the ASs 12,20, 22, 26, 28 and 32. In addition, a particular AS 12, 20, 22, 26, 28,or 32 appears to other ASs 12, 20, 22, 26, 28, or 32 as having a singlecoherent interior routing plan. A particular AS 12, 20, 22, 26, 28, or30 also presents a consistent picture of the locations, such as thedestination 34 or the source 11, that are reachable through it.

Each AS 12, 20, 22, 26, 28, and 32 also has a particular AS numberassociated with it. AS numbers are assigned by three registryorganizations, the American Registry for Internet Numbers (“ARIN”), theReseaux IP Europeans (“RIPE”), and the Asia-Pacific Network InformationCenter (“APNIC”). Thus, each of the ASs 12, 20, 22, 26, 28, and 32 hasan AS number irrespective of where in the world they are located. An ASnumber is assigned because it is a prerequisite for the use of BorderGateway Protocol version 4 (BGP4). BGP4 is the official and onlyinter-AS routing protocol currently used in the Internet 10. Therefore,an AS 12, 20, 22, 26, 28, or 32 can be viewed as a collection ofInternet routers, such as the routers 14 or 33, which all use the sameAS number to connect to the rest of the Internet 10. In the portion ofthe Internet 10 pictured in FIG. 1, the AS number for each of the ASs12, 20, 22, 26, 28, or 32 is the number following the dash in FIG. 1.For example, the AS number for the AS 12 is one, while the AS number forthe AS 20 is two.

In order to determine how to send a data packet to a destination such asthe destination 34, an AS 12, 20, 22, 26, 28, or 32 communicates withthe ASs 12, 20, 22, 26, 28, or 32 which may or may not be directlyconnected. For example, the AS 12 is connected directly to the AS 20 viaa high-speed telecommunications link 15. Similarly, the AS 20 isdirectly connected to the AS 26 Via link 16. However, the AS 12 is notdirectly connected to the AS 26. If the router 14 at the AS 12 is tocommunicate with the router 33 at the AS 32 or a route (not shown) inthe AS 20, there must be some method for the AS 12 to be informed of thehow to reach another AS 20, 22, 26, 28, of 32. BGP4 is the protocol thatallows the transmission of this reachability information.

Using the reachability information transmitted via BGP4 by each AS 12,20, 22, 26, 28, and 32 and the addressing information in data packets,the ASs 12, 20, 22, 26, 28 and 32 can communicate and transfer datapackets between the source 11 and the destination 34. Each AS 12, 20,22, 26, 28, and 32 transmits the reachability information describing therange of its assigned IP addresses. The other ASs 20, 22, 26, and 28receive and relay this reachability information. For example, both theAS 12 and the AS 32 will transmit BGP messages describing the range ofIP addresses which are assigned to the AS 12 and the AS 32,respectively. The AS 12 and the AS 32 thus broadcast their reachabilityinformation. The AS 26 receives the reachability information for the AS32 and relays the information to the AS 20. The AS 20 receives thereachability information for the AS 32 from the AS 26. The AS 20 informsthe AS 12 that the AS 32 and, therefore, the IP addresses assigned tothe AS 32 are reachable via the AS 20. Similarly, the AS 20 receives thereachability information from the AS 12 and relays the information tothe AS 26. The AS 26 receives the reachability information for the AS 12and informs the AS 32 that the AS 12 and, therefore, the IP addressesassigned to the AS 12, are reachable via the AS 26. The AS 12 and the AS32 announce their IP networks or announce their routes. By acting as agateway between the AS 12 and the AS 32, the AS 20 and the AS 26 areproviding transit service to both the AS 12 and the AS 32. Thus, the AS20 and the AS 26 allow data packets to transit the AS 20 and the AS 26,respectively. Consequently, data packets can be transferred between thesource 11 and the destination 34 using the IP addresses of the source 11and the destination 34, respectively, as the destination address.

In the context of the exchange of information discussed above, the AS 12and the AS 20 are said to “peer” with each other because they aredirectly exchanging reachability information with each other via BGP4.Similarly, the AS 20 and the AS 26 are peering with each other. The AS26 and the AS 32 are also peering with each other. Although the routedescribed in above example allows the AS 12 and the AS 32 to communicatevia the AS 20 and the AS 26, this communication could also take place ina route through the AS 22 and the AS 26, a route through the AS 28, or aroute through the AS 22, the AS 20, and the AS 26. Thus, the AS 12 alsopeers with the AS 22 and the AS 28. Similarly, the AS 36 also peers withthe AS 22. The AS 32 also peers with the AS 28. The AS 20 also peerswith the AS 22.

Some ASs 22, 26, 28, or 32 establish BGP4 peering by using a NAP, suchas NAP 24 and NAP 30. Each NAP 24 and 30 is a common physical locationwhere many ASs can interconnect with each other using high-speed localarea network technology. Thus, the NAP 24 allows the As 22, the AS 20,and the AS 26 to interconnect. Similarly, the NAP 30 allows the AS 28and the AS 32 to connect. Other ASs (not shown) may also connect to theNAP 24 and the NAP 30.

The Internet 10 has multiple routes between different locations. Forexample, there are multiple routes between the source 11 and thedestination 34. One route is via the AS 20 and the AS 26. Another routeis via the AS 22 and the AS 26. On such a route, a data packet wouldalso pass through the NAP 24. A third route is via the AS 28. A datapacket would pass through NAP 30 on such a route. A fourth route is viathe AS 22, the AS 20, and the AS 26. This route crosses through NAP 24.Having multiple routes is desirable feature because redundant routesallow data packets to follow an alternate route if any single route goesdown. However, whenever there are multiple routes to a destination, therouter 14 makes a routing decision as to which route to choose for apacket destined to be delivered to the destination 34. The decision asto which route to take is important because the route that a data packettraverses when crossing the Internet 10 determines how quickly thatpacket will reach its destination and the probability that the packetwill be dropped due to congested links along the route.

The routers within an AS 12, 20, 22, 26, 28, or 32 select a route fordata packets to use when traveling via the Internet 10. For example, therouters 14 and 33 select the routes for data packets to travel betweenthe source 11 and the destination 34. A data packet from the source 11includes a destination address indicating the destination 34. Thedestination address typically includes the IP address of the destination34. Using the destination address and BGP4, the router 14 selects aroute to send the data packet to the AS-6 32 and, therefore, to thedestination 34.

When the source 11 transmits a message, such as a data packet, to thedestination 34, the router 14 in the AS 12 makes a decision as to whichroute to take. In particular, the router 14 determines which of the ASs20, 22, or 28 the data packet will travel to next. As a result, therouter 14 decides the link 15, 16, or 17 on which to send the datapacket. The router 14 uses reachability information in order todetermine the route. The AS 12 receives reachability information viaBGP4 about the AS 32 from the AS 20, the AS 22, and the AS 28. Based onthis information, the router 14 in the AS 12 make a decision as to whichof the ASs 20, 22, and 28 directly linked to the AS 12 the data packetshould travel to. This decision is called choosing the “next hop”because a data packet is typically referred to as “hopping” from onerouter to another. After the next hop is selected, the data packettravels to the next AS 20, 22, or 28. The data packet then travelsthrough routers (not shown) in the next AS 20, 22, or 28. One suchrouter, at a border of the next AS 20, 22, or 28 determines thesubsequent AS which the data packet will hop to next. Thus, theserouters (not shown) will select one of the links 21, 24, and 29.

FIG. 2 depicts one conventional method 50 for selecting a route. Theconventional method 50 will be described in the context of routeselection being performed by the router 14. The conventional method 50is a next-hop method, which selects a next AS 20, 26, or 28, to whichthe data packet will hop. Although the complete conventional method forselecting a route includes more steps, only certain steps are shown.First, a local preference for each route is set, via step 52. The localpreference is a weight which can be assigned to a particular route. Thehigher the preference, the more likely that the data packet will travelvia the link for that route. If no local preferences are setspecifically, then each route is given the same default preference instep 52. If a route has a higher local preference, then via step 54 thatroute will be chosen. In step 54, therefore, it will be determined thatthe data packet will traverse the link 15, 16, or 17 for the routehaving the highest local preference associated. Because the defaultpreferences are typically used for all routes in step 52, step 54 willgenerally not select a route. If the local preferences are the same,then the route with the fewest number of ASs 12, 20, 22, 26, 28, and 32is chosen in step 56. The step 56 is known as choosing the route withthe AS path having the shortest length. The route is normally selectedin step 56 because the default preferences are generally used. In step56, therefore, it is determined that the data packet will travel via thelink 15, 16, or 17 for the route having the shortest AS path.

An AS path is typically defined as an ordered sequence of AS numbers,such as a sequence of AS numbers in the route from a source to adestination. Referring back to FIG. 1, the AS path for the route throughthe AS 22 and the AS 20 is four, two, three, six. There are four ASnumbers in this AS path. Therefore, this AS path has a length of four.The AS path through the AS 22 from the AS 12 to the AS 32 is four,three, six. There are three AS numbers in this AS path, so the length ofthis AS path is three. Similarly, the AS path through the AS 28 to theAS 32 is five, six, and has an AS path length of two. Finally, the ASpath through the AS 20 from the AS 12 to the AS 32 is two, three, sixand has a length of three. Using the conventional method 50, therefore,the router 14 will typically choose to send a data packet via the link17 to the AS 28.

Although the conventional method 50 selects a route allowing a datapacket to traverse the internet 10, one of ordinary skill in the artwill realize that the route selected may pass through overloadedsegments, which delays transmission of the packet or result in thepacket being dropped. This results in poor system performance. Althoughthe method 50 reduces the number of ASs 12, 20, 22, 26, 28, and 32,through which a data packet travels, the AS number, the destinationaddress, and the AS path do not indicate the geographic area of the ASs12, 20, 22, 26, 28, or 32, the source 11, or the destination 34. Inaddition, the ASs, such as the AS 28 and the AS 32, in the route havingthe shortest AS path may be widely separated geographically. As aresult, a data packet may take a very long time in traveling from the AS28 to the AS 32, increasing latency time.

In addition, the AS number, the destination address, and the AS path donot indicate the traffic on an AS, link, or NAP. The route selectedusing the conventional method 50 may, therefore, include overloaded ASs12, 20, 22, 26, 28 or 32 or overloaded NAPs 24 or 30. For example,assume that the AS 28 is overloaded. Similarly, assume that the NAP 30is overloaded. The method 50 will result in the data packet travelingvia link 17 even if another route would be more efficient. As a result,the data packet will travel through the AS 28 and the NAP 30, which areboth overloaded. Consequently, the data packet may be dropped ordelayed.

These problems may be exacerbated when the AS 20 and the AS 32 assignedthe address of the destination 34 are not in the same country as thesource 11. Because the data packet is traveling internationally, largergeographic distances may be involved. Thus, latencies introduced due tothe data packet traveling large distances are increased. For example,presume that the AS 20, the AS 26, and the AS 32 are in Great Britain,while at least the AS 12 is in the United States. Also suppose that theAS 28 is in Asia. Using the conventional method 50, the data packet willtravel from the United States to Asia, then to Great Britain. Becausethe data packet travels between three continents, the data packet maytake longer to reach the destination 34 than if the data packet traveledvia a route having a longer AS path.

Similarly, the fact that international links are involved may furtheraffect transmission of the data packet. For example, presume that the AS20, the AS 26, and the AS 32 are in Great Britain, while the AS 12, theAS 22, and the AS 28 are in the United States. Thus, the links 15, 25,and 31 are international links between Great Britain and the UnitedStates. International links are often highly overloaded. However, assumethat the link 15 can provide a much quicker route to the destination 34.The conventional method 50 may still determine that the data packet isto be sent to the AS 28 via the link 17 because this is the shortest ASpath. As a result, transmission of the data packet may be delayed or thedata packet may be dropped. The delay or probability that the datapacket is dropped may be higher because the link 17 is an internationallink very likely to be overloaded. As a result, the user at the source11 or destination 34 may not receive an important data packet or may notreceive the data packet in the requisite time.

The present invention provides a method and system for determining aroute for a packet traveling over at least one system from a source to adestination. A first geographic area corresponds to the source and asecond geographic area corresponds to the destination. The destinationhas an address which does not indicate the second geographic areacorresponding to the destination. In this aspect, the method and systemcomprise associating an address for the destination with the secondgeographic area to allow selection of the route for the data packetbased on the second geographic area and selecting the route based on asecond geographic area.

In a second aspect, the method and system comprise providing a directlink having a controllable amount of traffic and selecting the directlink as at least a portion of the route when a data packet to thedestination is to be routed.

In another aspect, the method and system function in an Internetenvironment. In this aspect, the source has a first Internet Protocol(“IP”) address assigned to a first autonomous system and the destinationhas a second IP address assigned to a second autonomous system. Thefirst autonomous system has a first geographic area, and the secondautonomous system has a second geographic area. In this aspect, themethod and system comprise obtaining the second geographic area for thesecond autonomous system, mapping the second geographic area to thesecond autonomous system such that the route can be selected based onthe second geographic area, and selecting a direct link to a thirdautonomous system having the second geographic area for at least aportion of the route.

The method and system also facilitate selection of a route for a datapacket. In this aspect, the method and system comprise obtaininginformation relating to an autonomous system. The autonomous system hasa geographic area. The information includes the geographic area. In thisaspect, the method and system also comprise associating the autonomoussystem with the geographic area to allow selection of the route based onthe geographic area.

Because the geographic area of the destination is taken into account, anefficient route between the source and the destination may be selected.Because a direct link having a controllable amount of traffic is used inone aspect, a more efficient route may be selected. Thus, delays intransmission may be reduced. In addition, the probability that a datapacket may be dropped during transmission may also be reduced.Consequently, system performance may be improved.

The present invention will be described in terms of routing data packetsto particular countries, particular sources of information, certainprotocols, and particular routers using certain algorithms to determinerouting of a packet. However, one of ordinary skill in the art willreadily recognize that this method and system will operate effectivelyfor other types of packets, other destinations, other sources ofinformation, other protocols, and other routers using other algorithmsto determine routing. Moreover, nothing prevents the method and systemfrom being used in a single country. The present invention will also bedescribed in the context of a performing route selection for an AS fromwhich a data packet originates. However, one of ordinary skill in theart will realize that the present invention may be used in another ASfrom which the data packet does not originate. The present invention isalso described in the context of selecting a route for sending a datapacket from a particular source to a particular destination. However,nothing prevents the method and system from being used in conjunctionwith a different source or destination.

To more particularly illustrate the method and system in accordance withthe present invention, refer to FIG. 3 depicting one embodiment of amethod 100 in accordance with the present invention for selecting aroute based on geographic area. The method 100 is discussed in thecontext of a data packet traveling from the source 11 to the destination34. The destination 34 has an address. In a preferred embodiment, theaddress is the IP address of the destination 34. A geographic areacorresponds to the destination 34. In some embodiments, the geographicarea corresponding to the destination 34 is the geographic area for theAS 32 assigned the IP address of the destination 34. In a preferredembodiment, the geographic area corresponding to the destination 34 isthe country or countries for the AS 32 which is assigned the IP addressof the destination 34. However, in an alternate embodiment, thegeographic area could be another area, such as a particular area inwhich the AS 32 is located or the geographic area in which thedestination 34 is located. Note that the location of the destination 34could be different from the geographic area of the AS 32 which isassigned the IP address of the destination 34.

The address is associated with a geographic area corresponding to thedestination 34, via step 102. The route for the data packet is thenselected based on the geographic area corresponding to the destination34, via step 104. In some embodiments, the data packet includes thedestination address, which is preferably the IP address of thedestination 34. In this embodiment, step 104 is performed using thedestination address of the data packet and the association between theaddress and the geographic area created in step 102. Also in a preferredembodiment, step 104 includes selecting a privately owned direct link toan AS in the same country as the AS 32 which is assigned the IP addressof the destination 34. In such an embodiment, the country of the AS 32is preferably represented by an International Standards Organizationcountry code (“country code”). In another embodiment, step 104 includesselecting a privately owned direct link to an AS in a country near thecountry in which the AS 32 is located.

FIG. 4 depicts a more detailed flow chart of a preferred embodiment of amethod 110 for selecting routes in accordance with the presentinvention. In discussing the method 110, it is presumed that the method110 is performed for a router 14 in the AS 12. The country and AS numberare obtained for the AS 32 which is assigned the IP address of thedestination 34, via step 112. Thus, in this embodiment, the geographicarea corresponding to the destination is the country or countries forthe AS 12 assigned the IP address of the destination. Also in apreferred embodiment, an AS number represents an AS. Each country ispreferably represented by its country code. The country for the AS 32 isthen mapped to the AS number of the AS 32, via step 114. Consequently,the IP addresses assigned to the AS 32 are also associated with thecountry for the AS 32. The country associated with the AS number is thenmapped to a particular link directly to the country, via step 116. Thus,the country associated with the AS 32 is mapped to the direct link 15 instep 116. In a preferred embodiment, the direct link is a privatelyowned link between a particular AS, such as the AS 12, and an AS in thesecond country. Also in a preferred embodiment, the traffic over thedirect link is controllable, for example by ensuring that the directlink is not overloaded. The link to the country is then selected tocarry the data packet, via step 118.

To more particularly describe the advantages of the methods 100 and 110,refer back to FIG. 1. Assume that the AS 12, the AS 22, and the AS 28are in a first country, such as the United States. Also assume that theAS 20, the AS 26, and the AS 32 are located in a second country such asGreat Britain. The link 15 is a privately maintained international linkdirectly between the AS 12 and the AS 20 in the second country. Thelinks 25 and 31 between the first country and the second country may beconventional international links and, therefore, subject to overloading.The methods 100 or 110 are performed for the router 14 in the AS 12.

The AS 32 assigned the IP address of the destination 34 is associatedwith the second country. The AS number of the AS 32 and the identity ofthe second country, Great Britain, are obtained in step 112. The secondcountry is mapped to the AS number of the AS 32 in step 114. Thus, step114 can be considered to associate the geographic area of the AS 32 withthe IP address of the destination 34 because the second country ismapped to the AS number of the AS 32 assigned the IP address of thedestination 34. The link 15 between the second country and the router 14in the AS 12 is mapped to the country, in step 116. Thus, in step 118,the route is selected so that the data packet travels via link 15 to theAS 20 in the next hop.

Because the next hop is through link 15, the speed and probability ofthe data packet not being dropped are improved. The link 15 is directlybetween the AS 12 and the country of the AS 32. Thus, a data packet fromthe source 11 will travel from the AS 12 to the AS 20 in the secondcountry. The data packet will then travel intra-country from the AS 20to the AS 26 and the AS 32. Consequently, the distance traveled by thedata packet being sent to the destination 34 is reduced. Thus, transittime is improved and the probability that the data packet will bedropped due to congestion is reduced.

The method and system in accordance with the present invention can alsobe viewed as selecting routes based on links coupled to the router thatis determining the route for a data packet. FIG. 5A depicts oneembodiment of such a method 200 for selecting a route in accordance withthe present invention. FIG. 5A will be discussed in conjunction withsending a data packet from the source 11 to the destination 34 inFIG. 1. The source 11 corresponds to a first geographic area and isassociated with a first AS 12. The destination 34 corresponds to asecond geographic area and is associated with a second AS 32. Althoughthe method 200 is also described as being performed for the router 14 inthe first AS 12, nothing prevents the method 200 from being performedfor another router in another AS. For example, the method 200 may beperformed for a third router (not shown) in a third AS (not shown)having a third geographic area.

A direct link having a controllable amount of traffic, such as the link15, is provided, via step 202. The direct link is between the AS 12routing the data packet and a particular AS 20. The AS 20 has anassociated geographic area and is preferably in geographic proximity tothe second AS 32. It is then ensured that the direct link will be usedwhen routing a data packet to the destination 34, via step 204. Thus,the data packet will travel via the direct link 15 to the AS 20, thenvia AS 26 to the second AS 32.

In a preferred embodiment, the direct link 15 is privately controlled.Thus, overloading of the direct link 15 may be prevented or reduced.Also in a preferred embodiment, the first geographic area and secondgeographic areas include the geographic area(s) for the first AS 12 andthe second AS 32, respectively. However, in an alternate embodiment, thegeographic areas could be other areas. For example, the first or secondgeographic area could include the particular areas in which the first orsecond ASs is located or could include the geographic area in which thesource 11 or destination 34 is located. Also in a preferred embodiment,the second geographic area is the same as the geographic area for the AS20. Consequently, the direct link is preferably to the AS 20 having thesame geographic area as the second AS 32. This aids in reducing thegeographic distance that the data packet travels. The transit time andprobability that a packet will be dropped are thereby reduced.

FIG. 5B depicts a more detailed flow chart of a method 210 for selectinga route in accordance with the present invention. For clarity, FIG. 5Bwill be discussed in conjunction with FIG. 1. Thus, the method 210 ispresumed to be carried out for the router 14 in the AS 12 coupled withthe source 11. However, nothing prevents the method 210 from beingcarried out for another router. The method 210 utilizes a geographicarea corresponding to the destination 34 as well as a direct link 15having a controllable amount of traffic.

An address is associated with at least one geographic area via step 212.Preferably, this is accomplished by associating the address with thegeographic area(s) of the AS to which the address has been assigned.Also in a preferred embodiment, the ASs are represented by their ASnumbers and the geographic areas by country codes. The geographic areais then associated with a direct link 15 having a controllable amount oftraffic, via step 214. In a preferred embodiment, this is accomplishedby associating the direct link 15 with the country code(s) of the AS 20and the AS 12 to which the direct link is coupled. Steps 212 and 214 arethen repeated for all addresses of interest, via step 216. The directlink 15 is then selected for a data packet whose destination address isone of the addresses in steps 212 through 216, via step 218.

When a route is chosen through a direct link via the method 200 or 210,the data packet may be more efficiently routed through the Internet 10.Preferably the link 15 is privately maintained, preventing overloadingof the direct link 15. When the router 14 routes a data packet using themethod 200 or 210, the router 14 will choose to send the data packet viathe direct link 15. In the method 210, this is because the AS 20 isassociated with the same geographic area as the AS 32. Thus, the datapacket is sent over a private link having a controlled amount of trafficto an AS 20 that may be geographically close to the AS 32. As a result,transmission time and probability of dropping the data packet areimproved.

Where the direct link 15 is an international link, this improvement inperformance may be even more substantial. The destination 34 maycorrespond to a country different from the country corresponding to thesource 11. Preferably, the country corresponding to the destination 34is the same as a country or the countries associated with the AS 20. Thelinks 25 and 31 may also be international links and highly oversold.

Transmission through one of these links 25 or 31, which be in the routeselected by the conventional method 50, may be highly inefficient.Because the AS 22, the AS 28, the NAP 24 and the NAP 30 may be indifferent countries from the AS 32, they may also be even more widelyseparated from the AS 32. In contrast, transmission via the link 15would be relatively efficient because the link 15 may not be oversoldand because the AS 20 connected to the link 15 may not be widely spacedfrom the AS 32. Consequently, transit time and probability that a packetwould be dropped may be substantially lowered.

FIG. 6 depicts a flow chart of a preferred embodiment of a method 220 ofselecting a route in accordance with the present invention. Indiscussing FIG. 6, it will be assumed that the method 220 is beingperformed for the AS 12. Via step 222, it is determined which countriesare directly connected with the AS 12 via links having a controllableamount of traffic. Preferably, the countries are directly connected withthe AS 12 through privately maintained links, such as the link 15. It isdecided that these direct links 15 will be used when routing datapackets to an AS 20, 22, 26, 28, or 32 in that country or in a nearbycountry, via step 224. Thus, the criteria determined in step 224 ensurethat data packets will traverse the Internet 10 from the AS 12 throughdirect links 15, where possible. It is then decided that the route alsocrossing fewer NAPs 24 or 30 will be used, via step 226. A route mostclosely fitting these criteria is then selected via step 228.

It is desirable to select a direct link which is privately maintained instep 224 because the traffic on such links 15 can be controlled andbecause the direct link 15 is to an AS 20 that may be relatively closeto the AS 32. Thus, even though the link 15 is an international link,the link 15 should not be overloaded. In addition, the data packet maynot need to travel to ASs widely separated from the AS 32 assigned theIP address of the destination 34. It is desirable to cross few NAPs 24or 30 because NAPs 24 and 30 typically have a great deal of traffic.Therefore, a route having relatively low traffic will be selected instep 228. Consequently, transmission time and probability that the datapacket will be dropped is reduced.

FIG. 7 depicts a more detailed flow chart of a preferred embodiment of amethod 230 in accordance with the present invention. In discussing themethod 230, it is presumed that the method 230 is performed for a router14 in the AS 12. In a preferred embodiment, the router 14 utilizes anext-hop method, discussed with respect to FIG. 2. Referring back toFIG. 7, a country to which the router 14 connects directly is selected,via step 232. Thus, the country to which the link 15 connects the router14 is selected in step 232. Preferably, the link is privately owned ormaintained and has a controllable amount of traffic. In other words, theoverloading of the link can be prevented. A list of the AS numbers forthe ASs 20, 26, and 32 within that country is then produced, via step234. Via step 236, the local preferences are set so that the link 15 ispreferred when the router 14 receives a data packet having a destinationaddress for the destination 34 having its IP address assigned to an ASin the country, such as the AS 32. In a preferred embodiment, step 236is performed by setting the local preference to an arbitrary valuegreater than the default value when the destination 34 is associatedwith an AS, such as the AS 32, in the country. Steps 232 to 236 are thenrepeated for each country (not shown) to which the AS 12 is directlyconnected, via step 238. Via step 240 the next hop for the data packetis selected in accordance with the preferences set in step 236.

Thus, referring back to FIG. 1, the router 14 will select the routethrough the link 15 when the methods 200, 210, 220, or 230 in accordancewith the present invention are used. The route through the link 15, isthe only route directly to the AS 20 in the same country as the AS 32assigned the IP address of the destination 34. Moreover, the routethrough the link 15 does not cross the NAP 24 or the NAP 30. Thus, thelocal preference for the route through the link 15 will be set high andthe data packet will travel via link 15 on the next hop. The link 15will be selected even though the AS path length is three for the routethrough the link 15, while the AS path length through the link 17 istwo. As a result, the data packet will traverse a route that is lessoverloaded. The data packet may, therefore, have a reduced transmissiontime and a lower probability of being dropped during transit.

FIG. 8 depicts a method 250 in accordance with the present inventionwhich has been extended to nearby countries. Such nearby countries arelogically connected to a directly connected country in a non-overloadedfashion. In discussing the method 250, it is presumed that the method250 is performed for a router 14 in the AS 12. Thus, a nearby country isnear to a country having a direct link 15 to the AS 12. The nearbycountry is treated as part of the country directly connected to the AS12. Thus, a list of ASs (not shown) in the nearby country is generated,via step 252. The AS numbers for these ASs are then associated with thecountry to which the AS 12 is directly connected, via step 254. Thelocal preferences of the country to which the AS 12 is directlyconnected are then applied to each AS in the nearby country, via step256. Because of how these preferences are set, the route through thedirect link is then selected, via step 258. As a result, the data packetmay be sent through a relatively low traffic route even where the AS 12is not directly connected to the country for the AS (not shown) assignedthe IP address of the destination (not shown).

FIG. 9 depicts an embodiment of one method 300 for associating thedestination address with a geographic area corresponding to thedestination. Information relating to an AS of interest is obtained viastep 302. The AS of interest is assigned IP addresses, such as thedestination address. The information includes the geographic area(s) forthe AS of interest. In one embodiment this information also includes thecountry code(s) or country/countries of the AS. Also in one embodiment,the information is obtained using the AS number of the AS of interestThe geographic area(s) of the AS are then associated with the address sothat a route can be selected based on the geographic area, via step 304.In a preferred embodiment, this includes associating the AS number withthe country code. Also in a preferred embodiment, step 304 includescreating or adding to a database which can be used when a router, suchas the router 14, selects a route. Steps 302 and 304 are then repeatedfor all ASs of interest, via step 306.

FIGS. 10A through 10D depict embodiments of the method 300 forassociating one or more geographic areas with an AS when the informationrelating to the ASs is located in an accessible database. FIGS. 10Athrough 10D will be discussed in the context of routes being selected bya router 14 in the AS 12. As discussed previously, AS numbers assignedby ARIN, RIPE, and APNIC. Each of these organizations maintains apublicly-accessible database of its AS number assignments, includingpostal address and other contact information for the assignee of each ASnumber. Each of the three public databases is in a distinct formatdesigned to be human-readable, not machine-parsable. The method 300obtains the appropriate information from the databases and converts theinformation into a format that can be used when routing data packets.Thus, the method 300 preferably commences after it has been determinedwhich database contains information relating to the AS 12, 20, 22, 26,28, or 32 that is of interest.

FIG. 10A depicts an embodiment of a general method 310 for associatingan address with a corresponding geographic area for a general externaldatabase. The ASs 20, 22, 26, 28, and 32 for which the AS 12 receivesreachability information are determined, via step 312. The appropriateexternal database for one of the ASs 20, 22, 26, 28, or 32 is accessed,via step 314. The database includes information relating to certain ofthe ASs 20, 22, 26, 28, or 32. The information includes the designationof the ASs 20, 22, 26, 28, or 32 and the geographic area of the ASs 20,22, 26, 28, and 32 having information in the database.

In one embodiment, designation of the AS 20, 22, 26, 28, and 32 is itsAS number. In one embodiment, geographic area of the AS 12, 20, 22, 26,28, and 32 is indicated by its country code. Note that a particular oneof the ASs 20, 22, 26, 28, or 32 may have more than one country codeassigned to it. The information relating to a particular AS, such as theAS 20, 22, 26, 28, or 32, is found via step 316. In one embodiment thisinformation is found by using the AS number for the particular AS 20,22, 26, 28, or 32 that is of interest. The information for theparticular AS 20, 22, 26, 28, or 32 is then parsed to find thegeographic area, via step 318. In one embodiment, the country code forthe AS 20, 22, 26, 28, or 32 is found in step 318.

If more than one country code is assigned to an AS 20, 22, 26, 28 or 32,then more than one country code is found in step 318. The geographicarea is then associated with the designation of the AS 12, 20, 22, 26,18, or 32, via step 320. In a preferred embodiment, step 320 includescreating a database associating the country code of an AS 20, 22, 26,28, or 32 with its AS number. If an AS 20, 22, 26, 28, or 32 has morethan one country code, then the step 320 includes creating a databaseassociating all the country codes of the AS 20, 22, 26, 28, or 32 withits AS number.

In one embodiment, the database created in step 320 is machine-readableand can be used by the router 14 to select a route. In one embodiment,this database maps the country code(s) and AS number of an AS 12, 20,22, 26, 28 or 32 for the AS which will select the route and an AS in thesame country as or a nearby country to the AS 20, 22, 26, 28, or 32 ofinterest.

For example, when the method 310 is performed for the AS 12, thedatabase will map the AS number to the country code(s) of the country orcountries in which AS 12 is located. Via step 322, steps 312 through 320are then repeated for each of the remaining ASs 20, 22, 26, 28, or 32.Thus, in one embodiment, the method 310 provides a separate, privatelymaintained database, which can pinpoint the country or countries inwhich each AS 12, 20, 22, 26, 28, and 32 is located with a high level ofaccuracy.

FIG. 10B depicts a more detailed flow chart of a preferred embodiment ofa method 330 used to associate an AS with a geographic area using anARIN maintained database. The ASs 20, 22, 26, 28, and 32 for which theAS 12 receives reachability information are determined, via step 332.The database maintained by ARIN is then queried for informationregarding one of the ASs 20, 22, 26, 28, and 32, via step 334. In oneembodiment, step 334 includes querying the name server whois.arin.net toobtain the registration record for the AS number of the AS 20, 22, 26,28, or 32 that is currently of interest. Via step 336 the first fewlines of the registration record are scanned to look for addressinformation for the AS 20, 22, 26, 28, or 32. If the postal addresscontains a country name, that country's code is used to associate the ASnumber with the country code in step 338. If the postal address containsa country code, that country code is used to associate the AS numberwith the country code in step 338. In one embodiment, step 338 includescreating or adding to a database associating the AS number with thecountry code. The route announcements for the AS 20, 22, 26, 28, or 32of interest are also determined, via step 340. A route announcementincludes at least one network (not shown) associated with the AS 20, 22,26, 28, or 32 currently of interest. The database is queried forinformation regarding a route announcement, via step 341. Via step 342,the record of interest is scanned for the route announcement currentlyof interest.

In one embodiment, steps 341 and 342 include searching the list ofobjects in the ARIN maintained database for each network in the routeannouncement. If a network is found, then the country code for eachnetwork that is found is associated with the AS number of the AS 20, 22,26, 28, or 32 currently of interest, via step 344. Thus, in step 344,more than one country code can be associated with a particular ASnumber. In one embodiment, step 344 includes creating or adding to thedatabase associating the AS number with the country code. Next, steps341-344 are repeated for each route announcement. Then, steps 334through 345 are then repeated for each remaining AS 20, 22, 26, 28, or32, via step 346.

FIG. 10C depicts a more detailed flow chart of a preferred embodiment ofthe method 350 used to associate an AS with a geographic area using aRIPE maintained database. The ASs 20, 22, 26, 28, and 32 for which theAS 12 receives reachability information are determined, via step 352.The database maintained by RIPE is then queried for informationregarding one of the ASs 20, 22, 26, 28, and 32, via step 354. In oneembodiment, step 354 includes looking up the RIPE aut-num object for theAS number of the AS 20, 22, 26, 28, or 32 that is of interest. Via step356 the final descriptive text line of the record is found and parsed tofind the country name or country code of the AS 20, 22, 26, 28, or 32that is of interest. Via step 358, whois.ripe.net is queried for thestring “ASxxxx” where xxxx is the AS number for the AS 20, 22, 26, 28,or 32 that is of interest. In this embodiment, step 358 also includessearching the returned text for certain records having one or moreaddress fields. Step 358 also includes parsing the final address fieldto find a country name or country code. If the address contains acountry name, that country's code is used to associate the AS numberwith the country code in step 360. If the address contains a countrycode, that country code is used to associate the AS number with thecountry code in step 360. In one embodiment, step 360 includes creatinga database associating the AS number with the country code. The routeannouncements for the AS 20, 22, 26, 28, or 32 of interest are alsodetermined, via step 362. The RIPE database is then searched for eachnetwork in a route announcement, via step 364. In one embodiment, step364 includes searching the list of inetnum objects in the RIPEmaintained database for each network in the route announcement. If thenetwork is found, then the country code associated with that network isfound and associated with the AS number of the AS 20, 22, 26, 28, or 32currently of interest, via step 366. In one embodiment, step 366includes creating or adding to the database associating the AS numberwith the country code. Thus, in step 366, more than one country code canbe associated with a particular AS number. Next, steps 364-366 arerepeated for each route announcement. Then, steps 354 through 367 arethen repeated for each remaining AS 20, 22, 26, 28, or 32, via step 368.

FIG. 10D depicts a more detailed flow chart of a preferred embodiment ofa method 370 used to associate an AS with a geographic area using anAPNIC maintained database. The ASs 20, 22, 26, 28, and 32 for which theAS 12 receives reachability information are determined, via step 372.The database maintained by APNIC is then queried for informationregarding one of the ASs 20, 22, 26, 28, and 32, via step 374. In oneembodiment step 374 includes looking up the APNIC aut-num object for theAS number of the AS 20, 22, 26, 28, or 32 that is of interest andparsing that object to find a country name or an country code. Theadministrative contact field of the aut-num object is then parsed todetermine if the NIC handle is of the form XXX-YY, where YY is thecountry code, via step 376. The technical contact field of the aut-numobject is then parsed to determine if the NIC handle is of the formXXX-YY, where YY is the country code, via step 378. The country code(s)found in steps 374, 376, or 378 and the code(s) for the country found instep 374 are then associated with the AS number of the AS 20, 22, 26,28, or 32, via step 380. In one embodiment, step 380 includes creating adatabase associating the AS number with the country code. The routeannouncements for the AS 20, 22, 26, 28, or 32 of interest are alsodetermined, via step 382. The RIPE database is then searched for eachnetwork in the route announcement, via step 384. If the network isfound, then the country code associated with that network is found andassociated with the AS number of the AS 20, 22, 26, 28, or 32 currentlyof interest, via step 386. In one embodiment, step 386 includes creatingor adding to the database associating the AS number with the countrycode. Thus, in step 386, more than one country code can be associatedwith a particular AS number. Next, steps 384-386 are repeated for eachroute announcement. Then, steps 374 through 387 are then repeated foreach remaining AS 20, 22, 26, 28, or 32, via step 388.

The methods 300, 310, 330, 350, and 370 associate the geographic areawith the destination address such that the geographic area correspondingto the destination address can be used to select a route. Preferably,this association is provided via a database in which the geographic areafor the AS assigned the IP address of the destination is mapped to theAS number of the AS and, therefore, to the IP address of thedestination. Consequently, a more efficient route can be chosen,allowing transit time and probability that a packet will be dropped tobe reduced.

Although discussed in the context of ASs 12, 20, 22, 26, 28, and 32, thepresent invention can be extended to the IP network (not shown) level.In such an extension, it is possible to map each known IP network to acountry code or other indication of geographic area corresponding to adestination. Each route would then be weighted based on the geographicarea of the route's corresponding network. This approach has theadvantage of increasing granularity at the cost of increased complexityand a large increase in the number of router configuration lines.

A method and system has been disclosed for improving the routes for apacket selected by a router. Although the present invention has beendescribed in accordance with the embodiments shown, one of ordinaryskill in the art will readily recognize that there could be variationsto the embodiments and those variations would be within the spirit andscope of the present invention. Accordingly, many modifications may bemade by one of ordinary skill in the art without departing from thespirit and scope of the appended claims.

1. A method for selecting a route for a data packet from a source to a destination, the source being associated with a first autonomous system and the destination being associated with a second autonomous system, a first geographic area corresponding to the first autonomous system and a second geographic area corresponding to the second autonomous system, the method comprising: associating an address for the destination with the second geographic area; associating the first autonomous system with the first geographic area; associating the second autonomous system with the second geographic area; and selecting the route based at least in part on the second geographic area prior to the data packet arriving at the second autonomous system. 